In the field of products concerning the optical disk technologies such as CD, DVD and the like, there is a tendency to increase both the storage capacity, and the speed of data transfer in order to be competitive and capture market share. There is also the tendency to include an increasing number of features into laser drivers. Additionally, factors such as media type, writing speed, disc format and drive optics necessitate particular write strategies. In order to be competitive and capture market share, there is a tendency to increase the number of features (e.g., formats) supported by a single laser diode driver (LDD), to thereby enable a single LDD to support both CD and DVD technologies, as well as new technologies such as Blu-ray Disk (BD).
Conventional LDDs suffer from the need for more and more pins as the number of features supported by LDDs increase. For example, conventional LDDs require an analog line and/or a digital line (or pair) for every output current level supported, which causes a high pin count as the number of output current levels supported increases. Further, each line is subject to noise pick-up or timing inaccuracy, leading to poor fidelity waveforms. Additionally, because of the remote control of output drive for both the write current and the oscillator timing, conventional LDDs also suffer from timing errors.
To solve the problems of conventional laser drivers, manufacturers began to incorporate write strategy generators (WSG) into LDDs. However, while WSG LDDs solve the above mentioned problems of conventional laser drivers, WSG LDDs include large amounts of complex digital circuits. Such circuits are costly. Additionally, such circuits increase the power consumption and heat output of the LDD. Further, many customers do not want to change the complex controller chip from a conventional type to a WSG type. If they do so, they often have difficulty learning to use and support the WSG that is within a WSG LDD.